This invention relates to polymer-containing polyether polyamines containing terminal aromatically bound amino groups and a process for their production.
It is known that polyurethanes which have been produced using so-called polymer polyols (i.e. polyether polyols predominantly graft-modified by polymers or copolymers of olefinically unsaturated monomers) have better properties than non-modified polyether polyols. In particular, the hardness and carrying capacity of flexible polyurethane foams are better when modified polyether polyols are used. These modified polyether polyols are also advantageous in that they can be adjusted to relatively low unit weights and they save raw materials. In addition, such modified polymer polyols produce flexible foams having a greater number of open cells, and reduced shrinkage during storage. Finally, it is possible that use of such modified polymer polyols (provided the parent polyether is suitably selected) will produce highly elastic, cold-hardening foams without use of special polyisocyanates which have been specifically adapted with respect to reactivity. Standard commercial products, particularly the tolylene diisocyanate predominantly used in the manufacture of flexible foams, may, however, be used with modified polymer polyols.
In addition to polyether polyols, polyether polyamines have also been used as starting materials in the production of polyurethanes. Polyether polyamines may be obtained by any one of a number of processes, as will be discussed in more detail hereinafter. Polyether polyamines are generally characterized by greater reactivity and also by properties modified through the formation of urea groups instead of urethane groups upon reaction with polyisocyanates.
U.S. Pat. No. 4,286,074 describes polymer modification of polyethers containing terminal amino groups by grafting with unsaturated monomers. In this disclosed process, polyethers containing terminal amino groups, are said to be made by addition of the terminal hydroxyl groups of polyether polyols with acrylonitrile, followed by hydrogenation of the nitrile groups. The products described are polyethers containing terminal, primary aliphatically bound amino groups.
It is also known that OH-groups may readily be cyanoethylated on reaction with acrylonitrile. In fact, tests in which polyether polyamines containing aliphatically bound, primary terminal amino groups were treated with acrylonitrile and/or acrylonitrile/styrene mixtures under graft polymerization conditions have shown that cyanoethylation to form tertiary and secondary amino groups occurs to such a considerable extent that very few primary amino groups remain intact. It follows from this that the grafting of aliphatic polyether amines with acrylonitrile or with monomer mixtures containing acrylonitrile (particularly the acrylonitrile/styrene mixtures used exclusively in polymer polyol technology) results in a partial loss of functionality. Such grafted polyether polyamines are unsuitable for the production of polyurethane plastics because they may cause chain termination to a significant degree.